The invention is directed to a method for automatic output power control of signal transmission between two network modules. Merely by way of example, the invention has been applied to control signal output power for a ZigBee module with optimized power consumption and improved wireless connection. But it would be recognized that the invention has a much broader range of applicability.
In networking communication application where a signal is sent out from a transmitter to a receiver, it is generally preferred that the transmitter is able to send the signal with an optimum output power so that the signal is sent with substantial power saving while having still sufficient strength at the receiver side to make a successful communication with an expected or valid quality. Especially for wireless technology, power saving would be an important concern for many field applications because most of field-deployed wireless modules are just powered by non-rechargeable batteries and expected to sustain their operations for long time. ZigBee wireless technology compliant with IEEE 802.15.4 standard is a low-cost, low-power, wireless mesh networking standard. The low cost feature allows the technology to be widely deployed in wireless sensor control and monitoring applications, the low power-usage feature allows longer life with smaller batteries, and the mesh networking feature provides high reliability and larger range. However, the mesh topology also has several draw backs. For example, it has higher communication overhead associated with increased latency and lower end-to-end performance compared to other type of networking topology such as star topology. In general, the meshed routing requires more complex network protocols, which means the routers require more embedded resources resulting in increased power consumption for each ZigBee module.
ZigBee protocols with embedded applications require lower data rates and much lower power consumption through network designs to conserve the power in slave nodes, comparing to other wireless technology such as Wi-Fi and Bluetooth. Further reducing transmission power consumption without sacrificing wireless connection quality, however, is still an important task. It is seen that techniques or methods for optimizing signal output power for ZigBee module with improved receiving sensitivity at the same time are highly desired. It would provide a beneficial basis for additional improvement in many ZigBee wireless communication and signal remote sensing applications.